1. Technical Field
The present disclosure relates to a circuit device, an oscillator, an electronic apparatus, and a moving object.
2. Related Art
In the related art, an A/D conversion circuit which performs analog-digital conversion (hereinafter, referred to as A/D conversion) for converting an analog signal to digital data is widely known. There are various types of A/D conversion circuits, such as a flash type, a successive comparison type, and a ΔΣ type. For example, JP-A-2011-223404 discloses a method of performing successive comparison type A/D conversion.
There are various circuits using temperature detection data which is a result of A/D conversion of a temperature detection signal (analog signal) from a temperature sensor unit. For example, in the related art, a temperature compensated crystal oscillator (TCXO) is known. The TCXO is used as, for example, a reference signal source or the like in portable communication terminals, GPS related apparatuses, wearable apparatuses, on-vehicle apparatuses, and the like. A technique disclosed in JP-A-64-82809 is known as related art for a DTCXO, which is a digital type temperature compensated oscillator.
In a circuit device which performs A/D conversion, situations greatly differ in an activation period, which is a period from activation of the circuit device to output of an initial A/D conversion result, and a normal operation period after the activation period. Specifically, whereas, in the activation period, previous A/D conversion result data is not acquired, in the normal operation period, past A/D conversion result data, especially A/D conversion result data at a nearby timing, can be referred to.
Particularly, in a case where temperature detection data which is A/D conversion result data of a temperature detection voltage is obtained, a high speed may be emphasized in the activation period, and more efficient processing may be performed by taking into consideration temperature changes under natural conditions in the normal operation period. However, in the techniques of the related art, an A/D conversion technique taking into consideration such differences in conditions is not disclosed.